The Global System for Mobile Communication (GSM) is a standard for digital wireless communications. GSM has much more services than just voice telephony. Additional services allow nowadays a great flexibility in where and when GSM phones are used. Today's second-generation GSM networks deliver high quality and secure mobile voice and data services (such as SMS/Text Messaging) with full roaming capabilities across the world.
The development of GSM Networks and terminals to support more advanced data bearer technologies has allowed for the introduction of new exciting data services. These technologies allow for a greater bandwidth and more capable execution environment, so permitting for the development of mobile applications. The world has become increasingly computer centric and computer applications are now used for a number of tasks such as communications, financial management, information retrieval, entertainment and game playing. It is a natural progression for the user to expect these applications to be available to them on their mobile terminal.
More information about GSM services can be found on http://www.gsmworld.com/technology/applications/.
In mobile networks people can be contacted by calling to their mobile telephone number or by sending to that number a so called short message by e.g. making use of the Short Message Service (SMS). The point-to-point Short message service (SMS) provides a means of sending messages of limited size to and from GSM mobiles. Detailed information can be found in the ETSI standard GSM 03.40 Version 5.3.0.
The Subscriber Identity Module (SIM) inside GSM phones is a smart chip that was originally designed as a secure way to connect individual subscribers to the network. There is an on-going evolution of the SIM into a standardized and secure application platform for GSM and next generation networks.
ETSI (the European Telecommunications Standards Institute) is a not-for-profit organization whose mission is to produce the telecommunications standards for use throughout Europe and beyond. The ETSI TS 100 977 V8.2.0 (2000–05) standard describes the interface between the SIM and the Mobile Equipment (ME) within the digital cellular telecommunications system.
The logical structure of files in SIM is hierarchical and there are three types of files, i.e. Elementary Files (EF), Dedicated Files (DF) and Master Files (MF), the last mentioned ones being highest in the hierarchy.
EFADN is an elementary file containing Abbreviated Dialing Numbers (ADN) and/or Supplementary Service Control Strings (SSC). In addition, it contains identifiers of associated network/bearer capabilities and identifiers of extension records. It may also contain an associated alpha-tagging.
The EFADN file is colloquially called the “phone book” file since the mobile phone user use it for fetching the right telephone number by name when trying to contact someone by calling or sending an SMS.
There are often difficulties in the communication as contact cannot be established due to unavailable or wrong contact information, absent people or the contact is tried to establish at a totally wrong occasion.
SyncML, described in http://www.syncml.org/technology.html is one attempt to try to solve this problem. It defines databases for synchronizing central database information with information on users' devices and vice versa. The SyncML solution, however, requires mobile terminals that support the SyncML protocol, which is a disadvantage, since most mobile stations do not have this support yet.